Joseph harbison



JosEPH HARRISON, J-R., y,or PHILADELPHIA,@PENNSYLVANIA j Latas ,Patent No. 75,754, ma March 24, 186s.

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Be it known that I, `.IOSEPIf HARRISON, Jr., of Philadelphia, State of Pennsylvania, have invented an'v improved SafetynApparatus for Stea'mJBoilers; and I' do hereby declare the following to be a full, clear, and

exact description of the same.v v p -My invention consists of. a tube, communicating at one end with a steam-boiler,- and closed at the opposite end, in combination witha pipecommuuicating with a reservoir orother supply of water under pressure, and a disk of glass', or'its equivalent, which, on beingacted upon by the tube, expanding, when steam is admitted to it, will'releasevthe water and permit .the same to flow on to the ignitedl fuel in the fireplace'.

In order to enable others skilled in theart to make and use my invention, Il will now proceed to describeits construction und operation, reference being'had to the accompanying drawing, which `forms a part of *this specification, and in which-` i p p l Figures I and '2 areisectional views illustrating one/modification of my `safetyapparatus for steam-boilers. Figure 3, a transverse section on the line-1 2, iig.y l. Figure,4,sections of parts 'of the apparatus detached from each other. Figure 5 represents a modification of part of my inwvention.; i f Similar letters refer to similar partsthroughout the several views. Y 0n reference vto figs. 1, 2, 3, and 4, A represents part of the front plate of a steam-boiler, and the line a the proper water-level in the same. Into the front of the boiler is screwedy atub'e, B, in the closed end offwhich is an adjustable set-screw, b, referred to hereafter. A larger tube, D, surrounds thetube B, and is at one end lsc'rewed to a collaryd, onA the latter;` the opposite end being open and projecting into cap, E, between `which .and a collar, e, on the tube, intervenes a.- suitable packing. A pipe, F, passes'through a central opening in the `cap E, against the inside of which the ilangef ofthe pipe bears. Between the end of the tube D andthe flange f of the pipe F intervenes the ring h of gum-elastic, the disk z' ofV glass, and a second gum ring,j, so that, on screwing the cap tight toits place, the glass will be securely confined between the gum rings, which, with the glass, .close the outer end o'f the tube f In applying the above-described instrument to a steam-boiler, the tube B is screwed into the plate Auf the same, at such a point below the proper water-line a that steam cannot gain access to the tube until the water has become too low.' l The screw islthen so adjusted that, when the cap E is screwed tight to the end of the external'tubeD, Athe-glass disk shall be free from contact w'ith the -head ofthe screw, but in proximity thereto.

The pipe F communicates with a hydrant, or with a reservoir or cisteru, so that there shall be `a constant l supply of water, under pressure, ready to rush`into the annular space between the' tubes D and Bthe moment the glass disk is broken.. l

As llong as a proper quantity of water remainslin the boiler, thereis little or no change in the temperature 4 in the internal tube B. which must be less than that of the lsteam in the boiler; consequently there can be no i nels to the fireplaceV aborvethe fuel.`

such expansion of the tube B'as will cause the head of the set-screw b to come'in contact -with the glass; but when the water becomes so low that steam will gain access to the internal tube, (see iig. 2,) and displace the water, ora portion of the water therein, the temperature of the tube will increase without a corresponding increase in the temperature oi' the exposed outer tube'D; consequently the inner tube willA expand, and its screw bqrill fracture" the glass and vpermit the water 'to rush from the pipe F into the annular space between the two tubes,I from which space it can` be directed throughop'enings m m, and through suitable ducts or cham With the exception of the wellLknowu fusible plug, the objections to which will be referred to hereafter,

'low-water indicators have generallylbeen so contrived that their'duty is limited to `the sounding of a whistle or other alarm as a warning of the condition of the' boiler tothe attendantengineer,who may not be at hand-to apply the proper remedies withthe promptitude necessary to prevent dangerousresults. The above-described instrument, however, at once, and without the aidof the engineer, extinguishes the fire the moment the water becomes low, while the `stoppage of Athe engine, and the unusual noise caused by the jets of water playing on to 4the fuel, will be warning suiicient tu the engineer thatY his services arelrequired.

The fusible plug, abovereferred to, hasbeen found to be inecient in many cases, and it has objection of permitting the smallamount of water which remains in the boiler to escape for the purpose of extinguishing the re when the water is low.

Another advantage of my invention is, that it may be so constructed as to be free from cocks and other external appliances,"which are common to many low-water indicators, and which muy be tampered with o r negligeutly operated bythe attendant so as to render the instrument useless.

In my invention,Y after the set-screw has been once adjusted, and the cap applied by responsible parties,

the eiciency of the instrument cannot be impaired unless -the cap be detached, and even this may be suitably locked, and the instrument thereby placed entirely beyond the control of the'engineer.

In order to 'increase the eiiiciency of the instrument as a safety-apparatus, I. in some cases, combine it with appliances by which the 'grate-bars of the furnace,y together with the fuel, will be precipitated into the ash-pit when the Water becomes too low. A mode of accomplishing this result is shown by '4, where G represents the fireplace, H the ash-pit, and I' one of the bearers for the grate-bars. Each bearer is supported at one end on an arm, k; both arms being secured to a shaft, n, from which projects an arm,p, the latter supporting a vessel, q, into which a stream of Water ows from the instrument when y'the glass breaks; the weight of the water in the vessel eventually depressing the latter, and moving the supporting-arms from the bearers, so that the bars and fuel will be precipitated into the ash-pit as the streams of water play on to the fire.

It is not essential that glass should be used to exclude the water, as other friable material'may'be employed, or a disk of th'n metal, suilicient to withstand the pressure of water, but easily penetrated 4by a puncturing termination of the expansion-tube, may be used. It is important, however, that the water should escape sud,v

denly, and in suicient quantities, when the expansion-tube performs its duty. The sudden escape ofthewatcr may be eilected through the ,medium of a valve, and by the,-action of the expansionstube. An instance of such an arrangement is illustrated in fig. 6, where F represents the water-supply pipe closed by a. valve, K, which is held upto its place by a clog, Il, the lower vend of the latter resting within a casing, M, at the end of the tube D.

When the tube B expands, its outer end comes in contact with the dog, and moves the same away from the valve, which, deprived of its support, falls into the casing M, and permits the water from the supply-pipe to rush into the tube D, and thence to the fireplace, the valve being elevated and the'Supporting-dog replaced after the instrument has performed its duty.

I claim as my invention, and desire to secure by Letters Patent- A tube B, communicating at one end with a steam-boiler, and closed at the opposite end, in combination with the water-supply pipe F,'and the disk t' of glass, or any equivalent to the same, the whole being constructed and operating substantially as and for the purpose herein set forth.

In testimony whereof, I have signed my name to this specicntion in the presence of two subscribing witnesses.

' JOSEPH HARRISON, Jn.

Witnesses 'IL Howscn,

Joins WHITE, 

